This invention concerns heat exchanger assemblies, for internal combustion engine vehicles including vehicles such as motor omnibuses, coaches and like multi-passenger road vehicles, which are hereinafter collectively referred to as xe2x80x9cbusesxe2x80x9d.
A problem common to vehicles is overheating caused by the engine cooling heat exchanger becoming blocked or partially blocked to the flow of air therethrough by the accumulation of dirt and debris on the heat exchanger (commonly called the xe2x80x9cradiatorxe2x80x9d). This problem is particularly severe in urban and city areas in which buses operate.
For many years buses were configured with engines at the front and the radiators mounted in front of the engines to face the incident air flow. To facilitate steam cleaning of such forward facing radiators, we developed a strong rectangular peripheral sub-frame in which a relatively weak radiator core and manifold assembly was supported and held by retaining means so that forwards removal of the retaining means enabled the assembly to be moved in a forwards direction (nominally perpendicular to the median plane of the sub-frame) to facilitate cleaning of the core without having first to dismantle the sub-frame from the bus.
However this expedient is not applicable to the newer rear engined buses, in which the packing density of the engine, its ancillaries and cooling system is much greater than that of front engined buses. Thus, at present it takes some 7 to 8 man hours to remove a radiator from a typical rear engined modern bus.
The current requirements for compact and complex heat exchanger installations comprising a radiator, an intercooler and an oil cooler with one or more cooling air flow boost fans and the cowlings thereof, exacerbate the problems of inaccessibility and cleaning (particularly removal for steam cleaning) of the radiator.
In order to solve the aforementioned problems, according to the present invention there is provided a heat exchanger unit which includes a core and manifold assembly supported by and mounted in a rectangular sub-frame, characterised in that the sub-frame comprises a U-shaped member, in that the opposed parallel limbs of the U-shaped member form confronting channels to receive side portions of the assembly, and in that the sub-frame further comprises a cross-member secured to the core and manifold assembly and releasably secured to the U-shaped member to retain said assembly in said channels.
Release of the cross-member allows said assembly to be slid out of the channels so that the assembly can be slid out of the sub-frame in the median plane of the frame.
The sub-frame preferably provides mountings for locating an intercooler to one side of the core and manifold assembly, and a fan and cowl to the other side of said assembly. The mountings for the intercooler are preferably provided on the cross-member. Further mountings may be provided on the sub-frame for an oil cooler alongside the intercooler.
The cross-portion of the U-shaped member joining the parallel limbs thereof preferably provides abutments for anti-vibration means providing support for said assembly, and, preferably, also for the intercooler.
The heat exchanger unit is preferably fitted to a vehicle with the U-shaped member in an inverted position so that the core and manifold assembly can be slid into and out of the sub-frame from beneath the vehicle.
The invention also provides a method of removing a radiator from a heater exchanger unit in which a rectangular sub-frame includes a cross-member which is secured to one end or margin of the radiator, which method is characterised in that said cross-member is separated from the rest of the sub-frame to allow the radiator to be slid out of the rest of the sub-frame in a direction extending in the installed plane of the radiator.
This method allows removal of the radiator without prior removal of other heat exchangers or cooling fans installed in planes alongside said installed plane of the radiator.